Palm activated drug delivery device

ABSTRACT

A device configured to administer a medication can comprise a lower housing that includes a housing latch. The device can further comprise a needle guard that is movable relative to the lower housing along a first direction from a first position to a second position so as to expose a needle, and an upper housing supported relative to the lower housing. The upper housing can be configured to move with respect to the lower housing along a second direction from a pre-use position to a dispensed position. The housing latch can releasably interfere with the upper housing when the upper housing is in the pre-use position so as to prevent the upper housing from moving toward the dispensed position, and the movement of the needle guard toward the second position, causes the interference to be removed, thereby allowing the upper housing to move toward the second position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/833,978, filed Mar. 15, 2013, which is a continuation-in-part of U.S.patent application Ser. No. 12/905,572, filed Oct. 15, 2010, whichclaims the benefits U.S. Provisional Application Ser. Nos. 61/361,983,filed on Jul. 7, 2010, and 61/252,378, filed Oct. 16, 2009, thedisclosures of all of which are hereby incorporated by reference as ifset forth in their entirety herein.

TECHNICAL FIELD

The invention generally relates to methods and devices for parenteraldrug delivery. The devices provide for assisted manual drug deliverywith confirmation of completion of the drug delivery process. Thedevices provide a system with improved safety and ease of use andaudible, or other forms of, feedback to the user to indicate when drugdelivery is in process, completed, or both, to avoid one or both ofincomplete dosing and wasted medication as well as to provide a systemwith improved safety and ease of use.

BACKGROUND

For many years, an accepted method for parenteral drug delivery has beenthrough the use of syringe and needle. The syringe contains a quantityof a drug sold either in a pre-filled syringe or introduced into asyringe by drawing the drug into a syringe from a vial or othercontainer. Syringes have been widely accepted due to their lowmanufacturing cost and simple, effective design. For the user, however,syringes and needles have a number of drawbacks.

One drawback is that many patients have a fear of needles. In instancesin which self-medication is required, such as those requiring multiple,daily injections, patients may not administer their medication accordingto their prescribed regimen due to the fear of needles, the pain that isoften associated with an injection, the dexterity that is required toproperly administer a drug via needle and syringe or other, similarfactors. For some, that have their vision, dexterity, or awarenessimpaired, self-administration via needle and syringe may presentadditional difficulties that can prevent them from receiving theirrequired medication.

There also are safety and disposal concerns associated with needles andsyringes not only for the patient, but for those around them that mayresult from contaminated needles, accidental punctures,cross-contamination, and the like, in addition to the social stigmaassociated with a needle and syringe drug-treatment regimen. Despitethese drawbacks, however, many patients are encouraged to use needlesand syringes to deliver their medication due to the ability to controlinsertion of the needle and the speed of the drug delivery when theplunger in the syringe is depressed and, therefore, control theirperception of pain and discomfort associated with this type of druginjection.

Several advances have been made over the years to help facilitateself-administration of medication. Such advances include smaller needleswith improved tip-geometry to reduce the pain. Safety syringes thatencase the needle before, after, or before and after use have been usedto minimize concerns over accidental punctures with needles. Improvedergonomics in syringe design, as well, have been promoted to reduce thedexterity required to accurately and safely self-administer medicationvia needle and syringe. Pre-filled disposable devices having aform-factor similar to that of a pen were developed to improve dosingaccuracy, and auto-injectors have been used to hide the needle from thepatient to reduce fears and safety concerns either by retracting theneedle or placing a shield around the needle.

While such advances have improved needle and syringe based drugdelivery, ergonomic designs, pens, and auto-injectors all retain asubstantial similarity to the original needle and syringe concept, thuslimiting their acceptance by patients who need to self-administer theirmedication. Current systems employ a form factor that suggests thecommon “grab and stab” injection technique, wherein the user grips thedevice in the palm and places the thumb over an activation button.

Current auto-injectors transfer control of drug delivery into the bodyto a mechanical system. Because such a system is highly dependent on thespecific mechanical design of the auto-injector, patients may requirespecialized training to use the device and still risk inaccurate dosing.This situation is highly problematic when delivering very expensivedrugs that might only be administered on a weekly or even moreinfrequent basis.

The typical method of use of current auto-injectors includes the patientholding the device against the skin for several seconds while the deviceis in the process of delivering medication. Many users, and the elderlyin particular, may experience fatigue in their arm or hand causing themto exert uneven pressure of the device against the skin, or they mayremove the device prematurely. Either situation can result in inaccuratedosing, wasted medication, increased discomfort, and the like. Under anyof these circumstances, the current devices and methods that include, orevolved from, the traditional syringe and needle system haveshortcomings that compromise the efficacy of a prescribed drug regimen.

Finally, as with any health-care related device or service, the cost ofany frequently used component of a treatment regimen must be considered.While providing drugs in vials that are used to fill empty syringes at,or about, the time of a patient's medication may provide the leastexpensive solution, it adds an additional opportunity for waste or lossof an expensive drug. If that drug requires refrigeration, it mayexperience degradation each time it is removed and reinserted into therefrigeration device before and after filling the syringe, which canlead to less than expected drug efficacy if the vial contains a quantityof drug that is delivered over a long period of time. While pre-filledsyringes offer an advantage in both reliability and convenience, suchdevices still have the inherent drawbacks previously recited.

With devices such as pre-filled auto-injectors, the device is mostcommonly manufactured for use with a wide variety of medications, but istailored to no one medication. Because such devices rely on mechanicalsystems employing springs to control the injection rate of the drug,many drugs of different viscosity or that require refrigeration andchange viscosity appreciably as a result of temperature change, may bedelivered too quickly or too slowly for the predetermined spring-forceof the auto-injector design. In many instances, too low a spring forcemay result in incomplete drug delivery, removal of the device beforecompletion of the delivery, or excessive pain and discomfort to the userresulting from a prolonged period during which the injection device isinserted into the body. Too high a spring force, however, can result indrug delivery that is so rapid that it degrades the drug, may result insyringe breakage, or may cause injection force pain to the patientcaused by rapid delivery of an acidic drug or by inducing a pressuregradient under the skin or in a vein.

Thus, there are many opportunities for advancement in the field ofepisodic, parenteral drug delivery that could overcome “needle-phobia”,reduce pain to the patient, and increase the safety, reliability andefficacy of many drug treatment regimen.

SUMMARY

In accordance with an embodiment, a device configured to administer amedication can comprise a lower housing that includes a housing latchand a syringe that is supported by the lower housing and is configuredto retain a medication. The syringe can have a needle configured to beinserted into tissue. The device can further comprise a needle guardthat is movable relative to the lower housing along a first directionfrom a first position to a second position so as to expose the needle,and an upper housing supported relative to the lower housing. The upperhousing can be configured to receive a manual force and move withrespect to the lower housing along a second direction opposite the firstdirection from a pre-use position to a dispensed position in response tothe manual force. The device can further comprise a plunger rod carriedby the upper housing and movable with the upper housing so as to advancerelative to the syringe when the upper housing is moved along the seconddirection. Advancement of the plunger rod relative to the syringe cancause the syringe to deliver the medication out the needle. The housinglatch can releasably interfere with the upper housing when the upperhousing is in the pre-use position so as to prevent the upper housingfrom moving toward the dispensed position, and the movement of theneedle guard toward the second position, can cause the interference tobe removed, thereby allowing the upper housing to move from the firstposition to the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments of the application, will be better understoodwhen read in conjunction with the appended drawings. For the purposes ofillustrating the present disclosure, there is shown in the drawingspreferred embodiments. It should be understood, however, that theapplication is not limited to the specific embodiments and methodsdisclosed, and reference is made to the claims for that purpose. In thedrawings:

FIG. 1A is a side elevation view of an embodiment of the presentinvention.

FIG. 1B is a side view of the embodiment of FIG. 1A after cap removal.

FIG. 1C is a side view of the embodiment of FIG. 1B after depression ofthe interlock button.

FIG. 1D is a side view of the embodiment of FIG. 1C after the needleguard has been retracted, exposing the needle.

FIG. 2A is a side view of the embodiment of FIG. 1D during druginjection.

FIG. 2B is a side view of the embodiment of FIG. 2A upon completion ofdrug injection.

FIG. 2C is a side view of the embodiment of FIG. 2B after the needleguard has been extended, concealing the needle,

FIG. 3 is a depiction of an exploded view of the embodiment of FIG. 1A.

FIG. 4 is a depiction of a cross-sectional view of the embodiment ofFIG. 1A.

FIG. 5 is a depiction of a partial cross-sectional view of a portion ofthe embodiment of FIG. 1A, depicting a latch.

FIG. 6 is a depiction of a partial cross-sectional view of a portion ofthe embodiment of FIG. 1A, depicting a latch.

FIG. 7 is a depiction of a cross-sectional view of the embodiment ofFIG. 2A.

FIG. 8 is a depiction of a cross-sectional view of the embodiment ofFIG. 2B.

FIG. 9 is a depiction of a cross-sectional view of the embodiment ofFIG. 2C

FIG. 10A is a side view of another embodiment of the present invention.

FIG. 10B is a side view of the embodiment of FIG. 10A after cap removal.

FIG. 10C is a side view of the embodiment of FIG. 10B after the needleguard has been retracted, exposing the needle.

FIG. 11A is a side view of the embodiment of FIG. 10C during druginjection.

FIG. 11B is a side view of the embodiment of FIG. 11A upon completion ofdrug injection.

FIG. 11C is a side view of the embodiment of FIG. 11B after the needleguard has been extended, concealing the needle.

FIG. 12 is a depiction of an exploded view of the embodiment of FIG.10A.

FIG. 13A is a perspective view of the lower housing of the embodiment ofFIG. 10A.

FIG. 13B is a perspective view of the middle housing of the embodimentof FIG. 10A.

FIG. 14 is a depiction of a partial cross-sectional view of a portion ofthe upper and middle housings of the embodiment of FIG. 10A.

FIG. 15 is a depiction of a latching mechanism of the embodiment of FIG.10A

FIG. 16 is a depiction of another latching mechanism of the embodimentof FIG. 10A.

FIG. 17A is a depiction of a cross-sectional view of a portion of theembodiment of FIG. 10A.

FIG. 17B is a depiction of a perspective view of a portion of the lowerhousing of the embodiment of FIG. 10A.

FIG. 18 is a cross-sectional view of the device of FIG. 10A.

FIG. 19 is an exploded, side view of still another embodiment of thepresent invention.

FIG. 20 is a depiction of a cross-sectional, side view of yet anotherembodiment of the present invention prior to use.

FIG. 21A is a perspective view of an alternative design of the lowerhousing of the embodiment of FIG. 10A.

FIG. 21B is a perspective view of an alternative embodiment of the lowerhousing of FIG. 10A.

FIG. 21C is a cross-sectional view of the lower housing of FIG. 21B.

FIG. 22A is a front perspective view of yet another embodiment of themedication delivery device, in a pre-use position, the medicationdelivery device including a lower housing, a middle housing attached tothe lower housing, an upper housing movably attached to the middlehousing from a pre-use position to a dispensed position, and a needleguard movable relative to the lower housing from a first position to asecond position and subsequently to a final position.

FIG. 22B is a front elevation view of the medication delivery deviceshown in FIG. 22A in a post-use position with the upper housingsubstantially covering the middle housing.

FIG. 22C is a cross-sectional view of the medication delivery deviceshown in FIG. 22A.

FIG. 22D is a cross-sectional view of the medication delivery deviceshown in FIG. 22B with the needle guard in the second position wherebythe needle is exposed.

FIG. 22E is a cross-sectional view of the medication delivery deviceshown in FIG. 22D with the needle guard in the final position wherebythe needle is encapsulated.

FIG. 23 is an exploded view of the medication delivery device shown inFIG. 22A, including a grip cap, housing body, and skirt of the upperhousing, syringe retainer, syringe, and needle shield.

FIG. 24A is a bottom perspective view of the upper housing body shown inFIG. 23, the upper housing body including a pair of guides that eachdefines an abutment surface and a guide channel.

FIG. 24B is a side elevation view of the upper housing body shown inFIG. 24A.

FIG. 24C is a cross-sectional view of the skirt shown in FIG. 23, theskirt including a body and four friction members defined as rails thatextend from the body.

FIG. 25A is a perspective view of the middle housing shown in FIG. 23,the middle housing including a sidewall and four friction membersdefined by cantilevered portions that extend from the sidewall.

FIG. 25B is an enhanced side elevation view of one of the cantileveredportions of the middle housing shown in FIG. 25A.

FIG. 25C is a cross-sectional view of the medication delivery deviceshown in FIG. 22A showing the ribs of the skirt interfering with thecantilevered portions of the middle housing when the upper housing ismoved along the middle housing from the pre-use position to thedispensed position.

FIG. 26A is a perspective view of the lower housing shown in FIG. 23,the lower housing including a pair of housing latches that areconfigured to interfere with the guides of the upper housing to maintainthe upper housing in the pre-use position and are also configured tointerfere with the needle guard to maintain the needle guard in thefinal position so as to prevent reuse of the device.

FIG. 26B is a front perspective view of the lower housing shown in FIG.26A.

FIG. 27A is a perspective view of the syringe retainer shown in FIG. 23,the syringe retainer being configured to retain the syringe.

FIG. 27B is a perspective view showing the syringe being inserted intothe syringe retainer of FIG. 27A.

FIG. 27C is a perspective view of the syringe and syringe retainercombination of FIG. 27B being inserted into the lower housing.

FIG. 28 is a perspective view of the needle guard shown in FIG. 23, theneedle guard including a pair of extensions that each includes a stopthat maintains a respective housing latch in interference with theguides of the upper housing, and a needle guard latch that is configuredto interfere with the housing latch after the needle guard moves fromthe second position to the final position.

FIG. 29A a partial front elevation view of the medication deliverydevice shown in FIG. 22A when the upper housing is in the pre-useposition and the needle guard is in the first position such that stopsof the needle guard extensions abut the housing latches and maintain thehousing latches in interference with the abutment surfaces of the upperhousing guides so as to maintain the upper housing in the pre-useposition.

FIG. 29B is a partial front elevation view of the medication deliverydevice shown in FIG. 29A with the upper housing guide removed forclarity when the needle guard has moved to the second position such thatthe stops of the needle guard extensions no longer abut the housinglatches.

FIG. 29C is a partial front elevation view of the medication deliverydevice shown in FIG. 29B with the upper housing moving toward thedispensed position and the housing latches being moved into the channelsof the upper housing guides.

FIG. 29D is a partial front elevation view of the medication deliverydevice shown in FIG. 29C with the upper housing in the dispensedposition.

FIG. 29E is a partial front elevation view of the medication deliverydevice shown in FIG. 29D with the upper housing guide removed forclarity when the upper housing is in the dispensed position and theneedle guard begins to move from the second position and toward thefinal position.

FIG. 29F is a partial front elevation view of the medication deliverydevice shown in FIG. 29E when the needle guard is in the final positionand the needle guard latches are in interference with the housinglatches to thereby lock the needle guard in the final position.

FIG. 30A is a front elevation view of the medication delivery deviceshown in FIG. 22A in a pre-use position.

FIG. 30B is a front elevation view of the medication delivery deviceshown in FIG. 30A with the cap removed so as expose the needle guard.

FIG. 30C is a front elevation view of the medication delivery deviceshown in FIG. 30B with the needle guard in the second position.

FIG. 30D is a front elevation view of the medication delivery deviceshown in FIG. 30C with the upper housing moving toward the dispensedposition.

FIG. 30E is a front elevation view of the medication delivery deviceshown in FIG. 30D with the upper housing in the dispensed position.

FIG. 30F is a front elevation view of the medication delivery deviceshown in FIG. 30E with the needle guard in the final position.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following detailed description is to be read with reference to thedrawings in which like elements in different drawings are identicallynumbered. The drawings, which are not necessarily to scale, depictexemplary embodiments for the purpose of explanation only and are notintended to limit the scope of the invention. The detailed descriptionillustrates by way of example, not by way of limitation, the principlesof the invention.

The present invention is a drug delivery device, and methods for itsuse, which device overcomes many of the limitations and drawbacks ofconventional syringes and needles as well as auto-injector-type devices.To overcome the drawbacks and limitations of prior devices and toaddress the unfilled needs in the art, embodiments of the presentlydisclosed device and methods include a device that is configured suchthat the user does not see and cannot touch the needle, reducingneedle-phobia and potential for needle contamination. This includesautomatic shielding of the needle after delivery of the drug.

Embodiments of the device have an ergonomic form-factor that permitsoperation one handedly and conveniently allows for alternate siteinjections, such as the leg, arm, or abdomen. In embodiments thatinclude a pressure-sensitive triggering, a needle guard latch inhibitsmovement of the needle. In this manner, the device includes a safetymechanism that will not allow the needle to be exposed if it is notpressed against the injection site.

In FIGS. 1A-1D is illustrated one embodiment of the device of theinvention that includes a window 104 to view the drug prior to use. Acolored indicator may appear in the window after the device has beenused, to provide a visual indication to the user of whether the device'sdrug has been spent. Further, after the drug is delivered, increasedsafety and reduction in the possibility of accidental needle puncturesis provided.

To ensure that the user is aware of the status of the drug delivery andwhether it is completed, this embodiment of the invention includes pawlsand ratchets, such as those illustrated by the pawl 117 and ratchet 116shown in FIGS. 4 and 7, that engage to produce one or more audibleclicks when the injection is completed. Such a mechanism may signal theuser that the dose has been delivered and the device can be removed fromthe skin, preventing premature withdrawal of the device from theinjection site. Thus, the user actively participates during the entiredelivery process, unlike conventional auto-injectors for which the usermay need to wait several seconds for an assurance that the full dose hasbeen administered.

To provide greater feedback to the user, the disclosed system of pawlsand ratchets also provides audible clicks and motion of the deviceduring delivery to indicate that the injection is progressing. In yetanother embodiment, a louder click at the end of delivery alone or incombination with a visual indicator provides 1 feedback confirming thatthe delivery is completed.

Moreover, the present invention has a friendly, unintimidating designand method of operation, unlike conventional needle safety devices andauto-injectors, which are reminiscent of syringes and discomforting tothe user. Additionally, unlike conventional auto-injectors, the usercontrols insertion of the needle and injection of the drug as describedhereinafter.

In FIGS. 1 through 9 are shown an exemplary device of the invention. InFIGS. 1A through 1D is shown an embodiment of the device in variousstages leading up to injection of the drug and in FIGS. 2A through 2C isshown the embodiment during and after injection of the drug. FIG. 1Ashows the device 100 in its pre-use configuration as it may be receivedby the user. In this relaxed position, upper housing 101 partiallyoverlies the proximal or uppermost portion of lower housing 102. Indescribing the various embodiments of the device, the term proximal isused in relation to the upper end of the device and distal is used inrelation to the bottom surface of the device. For example, in FIG. 1B,distal is used in relation to bottom surface or bottom 131 of device100.

As shown, the device's outwardly visible features include upper housing101, lower housing 102, cap 103, window 104, interlock button 105, gripring 106, bottom edge 111 of the upper housing 101 and dose indicator107. FIG. 3 is an exploded view of the components of this embodiment ofthe invention.

A preliminary step in using the device is to remove cap 103, which isremovably attached to lower housing 102, as shown in FIG. 1B. Removingthe cap 103 simultaneously removes needle shield 113 and exposes needleguard 108. Window 104 and needle guard slot 109, each of which arepreferably present on both sides of the device, allow the user to viewand inspect an internally housed syringe 118 and its drug contents.

In use, the device is grasped by placing the palm of the hand over thetop of the upper housing 101, similar to how one grasps a floor-mounted, automotive gear shift. Grip ring 106 provides a visual cue tothe user on how to grasp the device. In one embodiment, grip ring 106 iscovered, or coated, or made of a suitable elastomeric materialincluding, without limitation, neoprene rubber, urethane, polyurethane,silicone, natural rubber, thermoplastic elastomer (“TPE”), orcombinations thereof to provide a non-slip and comfortable grippingsurface.

The user presses the device, by downward pressure of the palm on gripring 106 and interlock button 105, against the body at the desiredinjection location, typically the top or side of the upper leg, theabdomen, or the side or back of the upper arm. The pressure of the palmon interlock button 105 causes it to deflect downwardly, as shown inFIG. 1C, which in turn unlatches needle guard latch 124, shown in FIG.5, allowing the needle guard 108 to slide upwardly, and exposing needle110 (note that some device components have been removed from FIG. 5 forillustration purposes). Needle guard latch 124 is formed integrally witha portion of the distal end of upper housing sleeve 120. Upper housingsleeve 120 is a hollow cylinder a portion of which resides in the upperhousing 101 and portion of which resides in lower housing 102 when thedevice is in the relaxed position. Upper housing sleeve 120 is fixedlyattached to upper housing 101 and performs latching functions and actsto trap biasing element 119 against lower housing 102 as described inmore detail below.

Needle guard latch 124 includes inwardly, with respect to thelongitudinal center axis A-A′ of the device, ramped surface 127 and stop130 at its uppermost end. To unlatch the needle guard latch 124, anoutwardly ramped surface 128, complementary to surface 127, that formsthe distal end of interlock button extension 123, engages ramped surface127 on the needle guard latch 124. Engagement of surfaces 127 and 128causes the needle guard latch 124 to deflect outwardly, with respect tothe center axis, removing stop 130 from blocking the upward movement ofneedle guard 108. The latching mechanism and needle guard 108 arepreferably configured so upward movement of needle guard 108 isprevented unless the interlock button 105 is fully depressed. Thisprotects the needle from contamination and damage due to contact withother surfaces, protects the user from accidental needle punctures, andshields the needle from view.

As the user continues to press downwardly on upper housing 101, needleguard 108 moves upwardly, exposing and allowing needle 110 to penetratethe user's skin, stopping when bottom surface 131of the lower housing102 is substantially flush against the skin. Once needle guard 108passes beyond stop 130, the user may release interlock button 105, orchose not to, without affecting the remaining injection steps. Wheninterlock button 105 is released, resilient member 121, returnsinterlock button 105 to the up position. Movement guide 132 acts toensure that interlock button travels straight up and down.

The needle insertion process described herein gives control of insertionto the user. This feature allows the user to take advantage of acommonly used method often employed by insulin-dependent diabetics: ifthe needle is brought into contact with the skin and held there withoutpiercing the skin, after a few seconds the user will no longer feel thepresence of the needle, at which point the needle can be inserted painfree by increasing the pressure applied to the needle.

After needle 110 has been inserted into the user, the injection processtypically begins, as shown in FIGS. 2A through 2C. With reference toFIG. 6, aA housing latch 122 that is a part of lower housing 102 isshown in close-up detail and prevents the upper housing 101 from movingwith respect to the lower housing 102 in the device's pre-use state(note that some device components have been removed from FIG. 6 forillustration purposes). When needle guard 108 has completed its upwardtravel, ramped surface 133 on needle guard 108 contacts a ramped portionof surface 134 that forms the end of housing latch 122, causing thehousing latch 122 to deflect inwardly, thus allowing the upper housing101 and upper housing sleeve 120 to move downwardly.

After inserting needle 110 into the body, the user maintains pressure onthe upper housing 101. As shown in FIGS. 3, 4, 7 and 8 a plunger rod 115pushes on a plunger 112. Plunger rod 115 is connected fixedly to theupper housing 101 and syringe 118 is secured to or held in a cylinderformed within lower housing 102. Thus, when the upper housing 101 movesdownwardly with respect to and over the lower housing 102, a drug insidethe syringe 110 is delivered through the needle 110 to the patient bythe downward movement of plunger rod 115 and plunger 112 within syringe118.

After the housing latch 122 is disengaged, a biasing element 119 thatsurrounds the distal end of upper housing sleeve 120, is freed from atensioned state to apply a downward force on the upper housing 101 byexerting a downward force on upper housing sleeve 120, which is fixedlyattached, at its uppermost end, to upper housing 101. Biasing element119 also can be used to provide energy for assisting with advancement ofplunger rod 115 and plunger 112 with the user providing additionalrequired force resulting in injection of the drug or the energy suppliedby the biasing element 119 may be sufficient only to advance plunger rod15 and plunger 112. In another embodiment of the present invention,biasing element 119 provides sufficient force to inject the drug,without additional force input required by the user, thus providing aninjection device in which the needle is manually inserted and the drugis automatically injected. The biasing element may be any componentcapable of exerting a downward force on upper housing sleeve 120 to thedegree desired and may be, without limitation, a spring, a compressedgas actuator, a hydraulic drive, a wax actuator, an electrochemicalactuator, a shape memory alloy, and the like and the combinationsthereof. In the embodiment depicted in FIGS. 1 through 9, the userprovides the additional force required to advance the plunger rod 115and plunger 112 by pressing downwardly on the upper housing 101. Thus,the force required by the user to inject the drug is reduced, in amanner analogous to the way power steering in a car reduces the forcerequired by the driver to turn the steering wheel. Unlike conventionalauto-injectors, the user contributes to the force required for injectionand the present invention provide the user control over the rate ofinjection of the drug.

Referring to FIGS. 4 and 7, cross sectional views of embodiments of thepresent invention are shown both before and after delivery of the drughas commenced, respectively. As the drug is being delivered, a pawl 117which is attached to upper housing sleeve 120 moves along a ratchet 116that is attached to the lower housing 102. The pawl 117 and the ratchet116 may serve, at least, the following two functions. First, separationof upper housing 101 from lower housing 102 by pulling them apart isprevented. Second, the motion of pawl 117 along ratchet 116 produces asoft clicking noise, providing feedback to the user that upper housing101 is moving and the drug is being delivered. Additionally, and asillustrated in FIG. 8, at the end of travel of upper housing 101, pawl117 may be configured to engage a deeper recess in ratchet 116, therebyproducing a louder clicking sound, which can provide an audible signalto the user that end of travel has been reached and the drug has beenfully delivered, and further locking the upper housing 101 in place toprevent resetting or reuse of the device.

Referring to FIGS. 2B and 8, when the drug is completely injected andupper housing 101 is at the end of its travel, bottom edge 111 of upperhousing 101 covers dose indicator 107. Dose indicator 107 is acircumferential, colored ring at the distal portion of lower housing102. This provides a visual cue to the user that the drug delivery hasbeen completed.

Prior to use, the patient can view the drug through window 104 toinspect it for clarity and particulates. After use, the plunger 112 canbe viewed in the window 104, indicating that the device has been used.Alternatively, the window can be designed such that the plunger rod 115as well is visible after the injection is complete. The plunger 112 andthe plunger rod 115 can be brightly colored to provide a clearindication to the patient that the device has been used.

Referring to FIGS. 2C and 9, after completing the injection, the userremoves device 100 from the skin, and needle guard return element 114causes needle guard 108 to extend over needle 110, protecting the userand others from accidental needle punctures. Needle guard return may beany element capable of causing needle guard 108 to extend over needle110 including, without limitation, a spring, a compressed gas actuator,a hydraulic drive, a wax actuator, an electrochemical actuator, a shapememory alloy, and the like and the combinations thereof. Once needleguard 108 is fully extended, a needle guard lock 125 engages a slot inneedle guard 108, preventing the needle guard 108 from retracting.Needle guard lock 125 is a cantilever latch extending inwardly from theinner surface of upper housing sleeve 120. Lower housing rib 126, a partof the lower housing 102, may be configured to prevent the needle guardlock 125 from engaging the slot in the needle guard 108 prematurelyduring delivery by blocking the slot. In another embodiment of thepresent invention, needle guard 108 may extend and lock in place ifdevice 100 is removed before delivery is complete, to prevent reuse, orsharing of the device.

With the assisted delivery approach offered by the present invention,the user is actively engaged during the entire delivery process. This isdistinguishable from the activation process for conventionalauto-inserters, in which after pressing the button, the user passivelywaits, for several second, for the drug to be delivered, sometimeswondering whether the injection is in process or not.

The assisted activation approach of the present invention has theadditional advantage that it reduces development time and costassociated with modifying the injection device for delivering differentdrugs because the user controls delivery speed by varying the forceapplied to the upper housing 101. If the plunger is slightly stuck, theuser can apply a little more force, unlike conventional auto-injectorsthat must be designed for worst case force requirements, that varydepending on the drug, cartridge, plunger, needle, and friction in themechanism.

In another embodiment, the interlock button 105 and the interlock spring121 can be omitted from the design. In this embodiment, the upperhousing 101 is free to move downwardly before hitting a stop. Thismovement is used to unlock the needle guard 108 using a mechanismsimilar the interlock mechanism described above, allowing the needleguard 108 to retract. Once the needle guard 108 is fully retracted, itmay disengage another latch that allows the upper housing 101 todiscontinue moving downwardly and inject the drug in a similar manner asis described above.

In FIGS. 10 through 18 is depicted yet another embodiment of theinvention. In FIG. 10A is shown device 200 with upper housing 205, lowerhousing 202 and middle housing 201 therebetween. Upper housing 205includes grip cap 228. In the relaxed position, upper housing 205partially overlies the proximal, portion of middle housing 201. Thedistal-most portion of middle housing 201 is fixedly seated in lowerhousing 202. Also shown in FIG. 10A are upper housing bottom edge 211,travel ridge 216, and window 204. Window 204 preferably is seated withinthe distal portion of lower housing 202. A second window, not shown,preferably is present on the device on the side opposite of window 204.

Cap 203 is removably attached to lower housing 202 and, in FIG. 10B, isshown removed from device 200 to expose needle shield 213, needle shieldclamp 217 and needle guard 208. During removal of cap 203, needle shieldclamp 217 grabs and simultaneously removes needle shield 213 exposingneedle guard 208 to the user. When the device user presses the needleguard 208 against the skin, this action causes needle guard 208 to slideupwardly exposing needle 210, as shown in FIG. 10C.

FIG. 12 is an exploded view of device 200. Grip cap 228 includes gripcap assembly pins 230 that fixedly secure grip cap 228 on upper housing205. Assembly pins 230 mate with holes 242 in upper housing 205.Preferably, assembly pins 230 are square in cross-section with roundedcorners providing an interfering surface between the corners of assemblypins 230 and holes 242. Guides 233 and plunger rod 215, which areintegral with and extend downwardly from the inner surface of grip cap228 as shown. Plunger rod 215 includes a damper 221 at its distal end.Also shown are syringe 218 with plunger 212 and needle shield 213.

In a preferred embodiment, the external surface of grip cap 228 iscoated with or formed from, or the entirety of grip cap 228 is formedfrom, a material capable of providing a soft, non-slip grip for theuser. Suitable materials for coating or forming the grip cap include,without limitation, elastomeric materials such as neoprene rubber,urethane, polyurethane, silicone, natural rubber, TPE and the like andcombinations thereof.

Upper housing 205 includes click latch 220, handle rib guide 238, andbottom edge 211. For click latch 220, as well as the other latches usedin the device, preferably at least two latches are used and the samelatches are symmetrically positioned with respect to each other tofacilitate smooth movement and operation of the device.

Middle housing 201 is shown in FIG. 12 with body 207 and handle guideslots 239 on the external surface of the proximal portion of body 207.When the device is in use, handle rib guides 238, which are an integralpart of upper housing 205, engage with and slide within handle guideslots 239, maintaining smooth and controlled motion of upper housing 205during drug delivery.

Body 207 may serve as a dose indicator because, as the device isactivated, upper housing 205 descends over body 207. When the completemedication dose has been delivered, body 207 is fully obscured by upperhousing 205 as shown in FIG. 11C. Preferably body 207 is colored, morepreferably with a bright color, or is patterned to provide easily viewedvisual feedback to the user that the dosing is progressing or has beencompleted. Optionally, a scale may be included on body 207 to visuallyquantify the amount of drug that has been delivered or remains to bedelivered.

With reference to FIG. 13, middle housing 201 also includes grip latches224, click latch capture slots 236, and needle guard latch 237. Griplatch 224 is a generally rectangular element movably attached at itsdistal-most portion to the inner surface 243 of middle housing 201 sothat it is capable of movement outwardly toward inner surface 243 uponapplication of force. Grip latch 224 also includes a stop surface 245and a triangular shaped stop 244 extending inwardly toward the device'scenter from one corner of its topmost portion. In the device's resting,pre-use position grip latch 224 prevents upper housing 205 from movingwith respect to middle housing 201 due to stop 245 interfering with thedownward travel of guides 233 of grip cap 228.

With reference to FIGS. 12 and 13, lower housing 202 is shown with lowerhousing base 206, end of travel ridge 216, window 204, housing latch229, guide slots 227 and syringe retainer clip 235. Cap 203 removablyattaches to lower housing base 206 via cap retainer ring 234. In use,lower housing base 206 contacts the user's skin and, thus, preferably ismade of any of the soft flexible materials suitable for use for grip cap228.

Window 204 provides an opening in lower housing 202 for viewing of thecontents of syringe 218. Window 204 is positioned such that the bottomof syringe 218 is visible to the user allowing the user to verify thatplunger 212 has reached the end of its travel to the bottom of thesyringe. Window 204 may be any convenient size and shape and preferablyis oblong in shape with its long axis aligned with the long axis of thedevice and syringe so that the desired length of the syringe is exposedto view.

Guide slots 227 maintain the alignment of three different components:guides 233 of grip cap 228; grip latch release 231; and needle guardextensions 241. Guide slots 227 ensure smooth activation of the deviceby maintaining alignment and vertical travel of upper housing 202 andneedle guard 208 and reliable latching and unlatching of grip latch 231.Housing latch 229 extending outwardly secures middle housing 201 tolower housing 202 by engaging a recess, that is not shown, in innersurface 243 of middle housing 201. In non-reusable embodiments of thedevice, the shape of latch 229 and the recess are such that the middleand lower housing cannot be separated. For reusable embodiments, therecess and latch are configured to enable the middle and lower housingto be pulled apart.

Referring to FIG. 12, needle guard 208 includes needle guard slot 209formed on one side by grip latch release 231 and the other side byneedle guard extension 241. Grip latch release 231 includes rampedsurface 240. Referring to FIGS. 14 and 15, ramped surface 240 of griplatch release 231 faces outwardly and, as grip latch 231 travelsupwardly, engages ramped surface 244 of grip latch 224, which facesinwardly, causing grip latch 224 to deflect outwardly, removing theobstruction to the downward movement of guide 233 and 205.

Needle guard slot 209 permits window 204 to be used to view the syringeand plunger as the plunger acts on the syringe at the end of theplunger's downward stroke. Additionally, needle guard return 214 lieswithin and at the bottom of a space formed by grip latch release 231 andneedle guard extension 241.

An inventive aspect of the device 200 is the way in which syringe 218 issuspended inside the device. With reference to Figs, 12, 13, and 17,syringe 218 is held between needle shield 213 and damper 221, each ofwhich are flexible components, to protect syringe 218 in the eventdevice 200 is dropped or otherwise mishandled. When the device isassembled, syringe 218 is loosely held within cavity 246 of lowerhousing 202 by retainer clips 235. Depending on the volume of medicationwithin syringe 218, when the device is in used, there may be some travelof upper housing 205 before damper 221 contacts plunger 212 and, duringthis initial downward travel, damper 221 acts as an air piston tocompress the air in the gap formed between the end of plunger rod 215and plunger 212, which provides a rate-dependent resistance to motion tothe initial downward motion of grip. When damper 221 moves fast, aircannot escape quickly enough to reduce the build-up of air pressure.Damper 221 may optionally include through-holes, that are not shown,therein to allow air to leak past damper 221. Alternatively, afriction-based resistance from the damper without pressure build-up, usea damper in which there is no leak and no rate dependence, orcombinations thereof may be used. Upon contact of damper 221 withplunger 212, damper 221 collapses inwardly towards plunger rod 215reducing the friction between damper 221 and the inside surface ofcavity 246.

With reference to FIGS. 10 and 11, when the user desires to use device200, the user removes cap 203 from lower housing 202, which actionsimultaneously removes needle shield 213 and exposes needle guard 208.The user grasps device 200 by upper housing 205, places the palm of thehand over grip cap 228 and presses downwardly on grip cap 228 whileholding the device 200 against the desired injection site on the body,which pressing action causes needle guard 208 to slide upwardly exposingneedle 210. Continuing application of pressure to grip cap 228 resultsin needle 210 penetrating the user's skin and sub-dermal tissue,stopping when lower housing base 206 contacts the skin surface or whenthe rim 245 reaches of needle guard 208 reaches the end of its travelwithin lower housing 202.

With reference to FIG. 15, when needle guard 208 reaches the end of itsupward travel within lower housing 202, ramped surface 240 of grip latchrelease 231 contacts the oppositely facing and complementarily rampedsurface 244 of grip latch 224 of middle housing 201 causing grip latch224 to deflect towards the inner wall 243 of middle housing 201. Thisaction removes stop surface 245 of grip latch 224 from interfering withthe downward travel of guide 233 of grip cap 228 freeing guide 233 andallowing upper housing 205 to move downwardly and over middle housing201.

When upper housing 205 moves downwardly, the medication inside ofsyringe 218 is delivered through needle 210 as plunger rod 215 anddamper 221 of grip cap 228 push downwardly on syringe plunger 212. Atthe end of the medication delivery, body 207 is substantially completelycovered by upper housing 205 and bottom edge 211 of upper housing 205has mated with the complementarily shaped travel ridge 216 of lowerhousing 202. Also, plunger rod 215, damper 221, and plunger 212 areclearly visible within window 204. All of these features provide theuser with visual confirmation that the drug has been delivered and thehard stop of bottom edge 211 against travel ridge 216 provides a tactileconfirmation to the user.

Additionally, a click mechanism is activated at the end of drug deliveryto provide audible feedback. With reference to FIG. 14, click latch 220is deflected outwardly when ramp 247 thereof contacts and slides pastthe top of middle housing 201. When the ramp 247 moves sufficiently fardownwardly, ramp 247 aligns with click latch capture slot 236 and theramp 247 slips into capture slot 236, which slot extends through thewall at the proximal portion of middle housing 201, and snaps againstthe outer surface of body 207 of middle housing 201 creating a clickingsound. In non-reusable versions of the device, click latch 220 ispermanently captured by capture slot 236 and cannot be reset. In apreferred embodiment, two click latches 220 are positioned at positions180 degrees opposite of each other in order to provide smooth activationof the device and to enhance the clicking and latching functions.

As the user removes device 200 from the skin, needle guard return 214,shown in FIG. 12 as a spring, that was compressed by pressing of device200 against the user's skin, expands causing needle guard 208 to extenddownwardly over needle 210 protecting the user from accidentalpunctures. In addition to a spring, the needle guard return may be acompressed gas actuator, a hydraulic drive, a wax actuator, anelectrochemical actuator, a shape memory alloy, and the like and thecombinations thereof. When needle guard 208 is fully extended, needleguard retainer 232 engages stop 248, shown in FIG. 13, on lower housing202 preventing needle guard 208 from separating from lower housing 202.In FIG. 16 is shown needle guard latch 237 moveably attached at itsdistal end to the inner surface 243 of middle housing 201. When needleguard 208 is upwardly traveling, needle guard latch 237 is deflectedoutwardly on contact with the outer surface of guide 233 or of needleguard extension 241. When needle guard 208 travels downwardly andextends to cover needle 210, needle guard latch 237 slips over the topof needle guard extension 241 preventing needle guard 208 from againretracting.

Prior to use, extension guides 233 of grip cap 228 retain needle guardlatch 237 in an outwardly deflected position allowing needle guard 208to retract for insertion of needle 210. Two needle guard retainers 232and needle guard latches 237 preferably are used and are located 180degrees apart around the central axis of the device 200. If the device200 is removed from the skin before delivery of medication is completed,needle guard 208 will extend to cover needle 210 and locks to preventreuse of the device. In an alternative, reusable embodiment, needleguard 208 extends, but does not lock in place in the event device 200 isremoved from the skin before delivery of medication is completed.

FIG. 19 is a depiction of an alternative, reusable embodiment of device200 in which upper housing 205 and middle housing 201 are separable fromlower housing 202. In this embodiment, the user separates the middle andlower housings, inserts syringe 218 into the lower housing and thenreattaches the middle and upper housings.

In FIG. 20 is depicted yet another alternative embodiment of device 200in which an assist drive 219 is included. Assist drive 219 may find itsgreatest utility in delivering viscous drugs. The assist drive 219applies a force between upper housing 205 and middle housing 201exerting a downward force on upper housing sleeve 120. This reduces theamount of downward force the user must apply to grip cap 228 in order toinject the drug. Assist drive 219 may be a spring, a compressedactuator, a hydraulic drive, a wax actuator, an electrochemicalactuator, a shape memory alloy or the like or combinations thereof.Alternatively, assist drive may provide sufficient force to inject thedrug, without additional force input required by the user, thusproviding an injection device in which the needle is manually insertedand the drug is automatically injected in a manner similar to aconventional auto-injector.

In FIG. 21 is depicted an alternative embodiment of lower housing 202 ofdevice 200 in which a resettable clicking mechanism for a reusabledevice is included. In this embodiment, guide slots 227 engage guide 225of clicker 222. Clicking device 222 is biased by needle guard return214. To set clicking device 222, the user presses down on one of clickerguides 225 until clicker latch 226 extends over clicking device 222holding it down. When grip cap 228 moves downwardly, at the end oftravel, guide 233 contacts a ramped surface on clicker latch 226 causingit to deflect inwardly and releasing clicker 222 to travel upwardlyunder the force of needle guard return 214. A click sound is generatedwhen click surface 223 of clicker 222 contacts lower housing 202signaling that the drug has been completely delivered. The compressingof needle guard return 214 is increased when needle guard 208 isretracted during injection of the drug, increasing the force applied tothe clicking device and the volume of the click sound. Alternatively,the click mechanism can be reset automatically when the user attachesthe upper housing to the lower housing upon loading a new syringe intothe device.

FIGS. 22A-30F depict yet another embodiment of the medication deliverydevice. As shown in FIGS. 22A-22E, and 23 a delivery device 300 that isconfigured to deliver a medication defines a central axis A, a proximalend P, and a distal end D that is spaced from the proximal end D alongthe central axis A. As shown in FIGS. 22A and 22B, the device 300 caninclude a lower housing 304, an upper housing 308, and a middle housing312 coupled between the lower housing 304 and the upper housing 308. Thedevice 300 can further include a needle guard 316 that is supported bythe lower housing 304 and a cap 320 that is removably coupled to thelower housing 304 such that when the cap 320 is removed, the needleguard 316 is exposed. The needle guard 316 is movable relative to thelower housing 304 along a first direction X₁ from a first positionwhereby a needle 332 of the device 300 is guarded (e.g. as shown in FIG.22C) to a second position whereby the needle 332 is exposed(e.g. asshown in FIG. 22D). When the device 300 is pressed against the tissuesurface, the needle guard 316 is configured to move from the firstposition to the second position to thereby allow the needle 332 of thedevice 300 to be inserted into the tissue. As shown in FIGS. 22C-22E and23, the needle guard 316 includes a needle guard return 317, illustratedas a spring 318 that is configured to cause the needle guard 316 to movefrom the second position toward a final position along a seconddirection X₂ that is opposite the first direction X₁ and over the needle332 as the needle 332 is removed from the tissue (e.g. as shown in FIG.22E).

With continued reference to FIGS. 22A, 22B, and 23, the upper housing308 is supported relative to the lower housing 304 and is configured toreceive a manual force and move with respect to the lower housing 304along the second direction X₂ from a pre-use position to a dispensedposition in response to the manual force. As shown in FIGS. 22A and 22Bthe middle housing 312 includes a body 315 that is exposed between theupper housing 308 and the lower housing 304 when the upper housing 308is in the pre-use position and substantially completely covered by theupper housing 308 when the upper housing 308 is in the dispensedposition. Therefore, the upper housing 308 is configured to move alongthe middle housing body 315 as the upper housing 308 moves toward thedispensed position.

As shown in FIG. 22B, the upper housing 308 can define a first or bottommating edge or surface 311 and the lower housing 304 can define a secondor upper mating edge or surface 313 that mates with the bottom edge 311of the upper housing 308 when the upper housing is in the dispensedposition. The edges 311 and 313 can be sinusoidal as illustrated and canprovide visual indication that the upper housing 308 has moved to thedispensed position. It should be appreciated, that the edges 311 and 313can have any configuration as desired. For example, the edges 311 and313 can be flat as desired.

With continued reference to FIGS. 22C-22E and 23, the delivery device300 further includes a syringe 324 that is supported by the lowerhousing 304 and a plunger rod 328 that is carried by the upper housing308 and movable with the upper housing 308 so as to advance relative tothe syringe 324 when the upper housing 308 is moved along the seconddirection X₂. The syringe 324 is configured to retain a medication andcarries the needle 332 that is configured to be inserted into tissue.Advancement of the plunger rod 328 relative to the syringe 324 causesthe syringe 324 to deliver the medication out the needle 332 and intothe tissue. As shown in FIGS. 22A and 22B, the delivery device 300further includes at least one window 336, such as a pair of windows 336that provides an opening into the lower housing 304 for viewing thecontents of the syringe 324. As shown in FIGS. 22A, 22B, and 23 thelower housing 304 and the middle housing 312 together define the windows336 such that the windows 336 are located proximate to a distal end ofthe device 300. Therefore, the windows 336 are positioned such that thebottom of the syringe 324 is visible to the user thereby allowing theuser to verify that the plunger rod 328 has reached the end of itstravel to the bottom of the syringe 324. The windows 336 can be oblongalong the first direction X₁ as illustrated, though it should beappreciated, that the windows 336 can have any size and shape asdesired.

As shown in FIG. 23, the cap 320 is removably attached to the lowerhousing 304 such that removal of the cap 320 exposes the needle guard316 and removes a needle shield 338 from the syringe 324 to therebyexpose the needle 332 within the needle guard 316. As shown in FIG. 23,the cap 320 includes a cap body 340 and a needle shield clamp 344attached to the cap body 340. The cap body 340 defines a cavity 348 thatreceives the needle guard 316 when the cap 320 is attached to the lowerhousing 304 and a cap retainer ring 352 that grips the lower housing 304to thereby removably couple the cap 320 to the lower housing 304. Asshown in FIG. 23, the cap retainer ring 352 defines a pair of detents356 that are configured to receive a pair of protrusions 350 defined bythe lower housing 304 to thereby removably couple the cap 320 to thelower housing 304. To remove the cap 320 the lower housing 304 candefine a pair of bumps on either side of the protrusions 350 that allowthe cap to be twisted off. For example, the bumps can engage camsurfaces on the cap such that when the cap is twisted the bumps push thecap away from the lower housing 304. It should be appreciated, however,that the cap retainer ring 352 can include any features that removablycouple the cap 320 to the lower housing 304 as desired.

With continued reference to FIGS. 22C and 23, the needle shield clamp344 can be coupled to the cap body 340 within the cavity 348. The needleshield clamp 344 is configured to grip the needle shield 338 when thecap 320 is coupled to the lower housing 304. The needle shield 338 isattached to the syringe 324 such that the needle shield 338 encloses theneedle 332. When the cap 320 is removed from the lower housing 304, theneedle shield clamp 344 grips the needle shield 338 such that the needleshield 338 is removed from the lower housing 304 along with the cap 320.When the cap 320 is removed, the device 300 can be positioned against atissue surface and subsequently activated so as to inject the medicationinto the tissue.

Now referring to FIGS. 23, 24A-24C, the upper housing 308 can include askirt 360, a housing body 364 mounted to the skirt 360, and a grip cap368 mounted to the housing body 364. As shown in FIGS. 24A and 24B, theupper housing 308 and in particular the housing body 364 includes a gripcap mounting member 372 and a pair of guides 376 that extend distallyfrom the grip cap mounting member 372 along the second direction X₂. Asshown in FIG. 23, the grip cap 368 can be coupled to the grip capmounting member 372 and the guides 376 can extend through the skirt 360when the housing body 364 is mounted to the skirt 360.

The grip cap mounting member 372 can be dome shaped so as to define asubstantially convex proximal surface 374 and a distal surface 375 thatis opposite the proximal surface 374. The grip cap 368 can also be domedshape and can be mounted to the grip cap mounting member 372 such thatthe grip cap 368 overlies the proximal surface 374. As shown in FIG.24A, the mounting member 372 can include a plurality of fixation members380 that extend from the distal surface 375. The fixation members 380can each define an aperture 381 that is configured to receive arespective fixation member such as a locking pin 382 defined by theskirt 360 to thereby couple the housing body 364 to the skirt 360. Itshould be appreciated, however, that the fixation members 380 and 382can have any configurations as desired. For example, the fixationmembers 380 of the mounting member 372 can define locking pins and thefixation members 382 of the skirt 360 can define apertures. It shouldalso be appreciated, that the grip cap 368 and the housing body 364 canbe integrally formed as desired and that the grip cap 368 and mountingmember 372 can have any shape as desired.

As shown in FIGS. 24A, the upper housing 308 can further include atleast one locking latch 390, such as a pair of locking latches 390 thatextend from the distal surface 375 of the mounting member 372 and towardthe lower housing 304. The locking latches 390 are configured to lockthe upper housing 308 in the dispensed position after the upper housing308 has been moved from the pre-use position to the dispensed positionso as to prevent reuse of the device 300. The locking latches 390 can beelastically flexible and can each include a flexing member 392 thatextends from the mounting member 372 and a protrusion 394 that extendsfrom a distal end of the flexing member 392 toward the central axis A.As shown in FIGS. 22C-22E the locking latches 390 face each other suchthat the protrusions 394 extend toward each other along a direction thatis transverse to the second direction X₂. As shown in FIGS. 22C-22E, asthe upper housing 308 is moved along the middle housing 312, the lockinglatches 390 will engage the lower housing 304 and flex away from eachother. When the upper housing 308 reaches the dispensed position thelocking latches 390 will move back toward each other such that theprotrusions 394 engage a corresponding latch member of the lower housing304 to thereby lock the upper housing 308 in the dispensed position.When the locking latches 390 engage the corresponding latch members anaudible click sound may be produced to thereby signify to the user thatthe injection is complete. It should be appreciated, however, that thelocking latches 390 can have any configuration as desired and that theupper housing 308 can have any number of locking latches as desired. Forexample, the upper housing 308 can include a single locking latch asdesired.

As shown in FIGS. 22C, 23, and 24A-24B each guide 376 of the housingbody 364 extends through the skirt 360 and into the middle housing 312.Each guide 376 can include a guide body 377 that is elongate along thesecond direction X₂ and extends from the mounting member 372 such thatthe guides 376 face each other along a direction that is transverse tothe second direction X₂. The guides 376 are configured to temporarilyinterfere with the lower housing 304 so as to maintain the upper housing308 in the pre-use position until the needle guard 316 has moved to thesecond position and the needle 332 is inserted into the tissue. In thisway, unintentional dispensing of the medication may be avoided.

As shown in FIG. 24B, each guide 376 can define an abutment surface 398that at least partially faces the lower housing 304 and a channel 400that extends through the guide body 377 from a distal end of the guidebody 377 and toward a proximal end of the guide body 377. The abutmentsurfaces 398 are configured to engage the lower housing 304 when theupper housing 308 is in the pre-use position to thereby maintain theupper housing 308 in the pre-use position until the needle guard 316 ismoved to the second position. The abutment surfaces 398 can be disposedproximate to the distal ends of the guide bodies 377. The abutmentsurfaces 398 can define a plane that is perpendicular to the firstdirection and can include an angled portion that defines a ramp thatleads into a respective channel 400. The channels 400 extend completelythrough the guide bodies 377 along a direction that is transverse to thesecond direction X₂ and extend along a substantial portion of the guidebodies 377 along the second direction X₂. The channels 400 areconfigured to act as a relief or a guide for the lower housing 304 whenthe interference between the upper housing 308 and the lower housing 304is removed and the upper housing 308 moves toward the dispensedposition. That is, the portion of the lower housing 304 that interfereswith the upper housing 308 will move within the channels 400 when theinterference is removed and the upper housing 308 moves toward thedispensed position. It should be appreciated, however, that the abutmentsurfaces 398 and channels 400 can have any configurations as desired.For example, the abutment surfaces 398 can be angled and the channels400 can extend into but not completely through the guide bodies 377 asdesired.

As shown in FIGS. 24C, the skirt 360 includes a skirt body 404 that hasan inner surface 408 that defines a channel 412 that extends completelythrough the skirt body 404 along the second direction X₂. The upperhousing 308 is coupled to the middle housing 312 such that the middlehousing 312 is received within the channel 412 and the middle housing312 is configured to move through the channel 412 as the upper housing308 is moved toward the dispensed position. As shown in FIG. 24C, theskirt 360 includes at least one friction member 416, such as fourfriction members 416 that extend from the inner surface 408 and towardthe central axis A. The friction members 416 are configured to interferewith respective friction members defined by the middle housing 312 tothereby create a friction force as the upper housing 308 moves from thepre-use position toward the dispensed position. The friction force addsresistance when the manual force is applied to the upper housing 308 tothereby prevent the upper housing 308 from moving suddenly along thesecond direction X₂. For example, the friction force may prevent theupper housing 308 from moving suddenly in situations where the syringe324 is only partially filled with medication and the plunger rod 328 isnot in contact with the plunger that is within the syringe 324. Thefriction force created by the friction members should be greater than orequal to the force of the compressed needle guard spring 318 when theneedle guard 316 is in the second position to thereby prevent the needleguard spring 318 from lifting the lower housing 304 and pulling theneedle 332 out of the tissue prior to the plunger rod 328 contacting theplunger. It should be appreciated, however, that the friction force canbe any desired force. For example, the skirt 360 and middle housing 312can be void of friction members such that the friction force issubstantially zero. It should be further appreciated, that the skirt 360can define any number of friction members 416 as desired.

With continued reference to FIG. 24C, each friction member 416 candefine a rail 420 that protrudes from the inner surface 408. As shown inFIG. 24C, each rail 420 can taper as the rail 420 extends from a distalend of the skirt 360 toward a proximal end of the skirt 360. Therefore,the frictional force can be greater when the upper housing 308 beginsmoving from the pre-use position than the frictional force when theupper housing 308 is near the dispensed position. It should beappreciated, however, that the rails 420 can have any configuration asdesired. For example, the rails 420 can be void of a taper such that thefriction force between the upper housing 308 and middle housing 312 isconstant along the entire movement of the upper housing 308.

Now in reference to FIGS. 25A and 25B, the middle housing body 315includes a sidewall 464 and at least one friction member 468, such asfour friction members 468 that are carried by the sidewall 464. Eachfriction member 468 is configured to interfere with a respective one ofthe friction members 416 of the upper housing 308. As shown in FIG. 25Aeach friction member 468 can be configured as a cantilevered portion 472that is coupled to the sidewall 464 at a hinge 474 such that eachcantilevered portion 472 is configured to flex relative to a centralaxis of the middle housing 312 (e.g. the central axis A) as the upperhousing 308 moves toward the dispensed position. As shown in FIG. 25A,the sidewall 464 is substantially cylindrical and includes four slots478 that each defines a respective cantilevered portion 472. Each slot478 extends from a proximal end of the middle housing body 315 andterminates at a respective hinge 474. In the illustrated embodiment, thehinges 474 are oriented such that the cantilevered portions 472 flexabout respective axes that are parallel to the central axis A. As shownin FIG. 25A, the cantilevered portions 472 define first and second pairsof cantilevered portions each having a first cantilevered portion 472 aand a second cantilevered portion 472 b. The first and secondcantilevered portions 472 a and 472 b of each pair extend away from eachother. That is the first cantilevered portions 472 a of the first andsecond pairs extend clockwise about the sidewall 464 and the secondcantilevered portion 472 b of the first and second pairs extendcounterclockwise about the sidewall 464. Therefore, each cantileveredportion 472 can be curved so as to define a radius with respect to thecentral axis A. It should be appreciated, however, that the cantileveredportions 472 can have any configuration as desired and the hinges 474can have any configuration as desired. It should be further appreciated,that the friction members 468 are not limited to cantilevered portions472 and can include any configurations as desired. For example, thefriction members 468 can be elastomeric pads on an external surface ofthe sidewall 464.

With continued reference to FIGS. 25A-25B, each cantilevered portion 472can be located proximate to the proximal end of the middle housing 312.Each cantilevered portion 472 can include an outer elastomeric portion480 that is configured to be in contact with a respective rail 420. Theelastomeric portions 480 can be used to increase the frictioncoefficient of the surfaces of the cantilevered portions 472 that are incontact with the rails 420 to thereby modify the resistance. As shown inFIG. 25C, initially, when the upper housing 308 begins to move from thepre-use position the thicker portion of the rails 420 are in contactwith the elastomeric portions 480 such that the cantilevered portions472 flex inward toward the central axis A and apply a biasing forceagainst the rails 420. The interference between the rails 420 and thecantilevered portions 472 creates a friction force that resists themovement of the upper housing 308 toward the dispensed position. As theupper housing 308 moves further toward the dispensed position, the rails420 taper such that the biasing force against the rails 420 decreasesand the resistance to the downward movement of the upper housing 308 islessened.

Now in reference to FIGS. 26A and 26B, the lower housing 304 includes abase 490 and a lower housing body 494 that extends from the base 490along the first direction X₁. The base 490 includes a skin facingsurface 498 that is configured to face an individual's skin when theneedle 332 is inserted into the tissue. The base 490 further defines acavity 502 that extends into the skin facing surface 498 and isconfigured to receive the needle guard 316 when the needle guard 316 ismoved to the second position. The lower housing body 494 defines a pairof first channels 506 a that extend along the lower housing body 494along the first direction X₁ and a pair of second channels 506 b thatextend along the lower housing body 494 along the first direction X₁adjacent the first channels 506 a. Each channel 506 a is sized toreceive a respective guide 376 of the upper housing 308 such that theguides 376 advance within the first channels 506 a along the seconddirection X₂ as the upper housing 308 is moved toward the dispensedposition. The second channels 506 b are configured to receive portionsof the needle guard 316 such that the portions of the needle guard 316are disposed between the lower housing body 494 and the guides 376 andmovable within the channels 506 b along the first and second directionsX₁ and X₂.

As shown in FIGS. 26A and 26B, the lower housing 304 further includes atleast one housing latch 510, such as a pair of housing latches 510 thatreleasably interfere with the upper housing 308 when the upper housing308 is in the pre-use position so as to prevent the upper housing 308from moving toward the dispensed position. As shown in FIG. 26B, eachhousing latch 510 includes a leg 512 that extends upward from arespective portion of the lower housing body 494 and a protrusion 514that extends from a proximal end of the leg 512 away from the centralaxis A and into the channels 400 defined by the guides 376.

The housing latches 510 are elastically flexible such that the housinglatches 510 are configured to flex or otherwise move out of interferencewith the upper housing 308 as the upper housing 308 moves from thepre-use position and toward the dispensed position. In particular, theprotrusions 514 engage the abutment surfaces 398 of the guides 376 tothereby prevent the upper housing 308 from moving toward the dispensedposition. When needle guard 316 has moved to the second position and thehousing latches 510 are free to flex, movement of the upper housing 308toward the dispensed position causes the protrusions to move into andalong the channels 400 of the guides 376 and thus out of interferencewith the upper housing 308. It should be appreciated, that the housinglatches 510 can have any configuration as desired and can extend fromany portion of the lower housing body 494. For example, each leg 512 canextend downward from a respective portion of the lower housing body 494.

With continued reference to FIGS. 26A and 26B, the lower housing 304further includes at least one latch member 530, such as a pair of latchmembers 530 that are configured to mate with the locking latches 390 ofthe upper housing 308 when the upper housing 308 is in the dispensedposition. As shown in FIG. 26A, each latch member 530 can define a ramp532 that extends from the lower housing body 494 and a shelf 534 at adistal end of the ramp 532. The shelf 534 defines a surface that facesthe distal end of the device. As the upper housing 308 is moved towardthe dispensed position, the protrusions 394 of the locking latches 390will ride along the ramps 532 and flex away from each other. When theupper housing 308 reaches the dispensed position, the locking latches390 will snap over the latch members 530 and return substantially totheir original positions such that the protrusions 394 engage theshelves 534 to thereby lock the upper housing 308 in the dispensedposition. In particular, the protrusions 394 abut the surfaces of theshelves 534 so as to prevent the upper housing 308 from moving backtoward the pre-use position. It should be appreciated, however, that thelatch members 530 can have any configuration as desired. For example,the latch members 530 can be slots defined in the lower housing body 494that receive the protrusions 394.

The contact between the protrusions 394 of the locking latches 390 andthe ramps 532 can create a friction force that adds to the resistance tothe downward manual force that is applied to the upper housing 308 tomove the upper housing 308 to the dispensed position. In this way thelocking latches 390 and latch members 530 can also be consideredfriction members. That is, the rails 420 and the cantilevered portions472 can be considered primary friction members and the locking latches390 and latch members 530 can be considered secondary friction members.

Now in reference to FIGS. 23 and 27A-27C, the syringe 324 can include abottom shoulder 540 that is proximate the needle 332 and an upper rim544 spaced from the bottom shoulder 540 along the first direction X₁. Asshown in FIGS. 27A-27C, the device 300 can further include a syringeretainer 548 that is configured to receive the syringe 324 and supportthe syringe 324 at the bottom shoulder 540. The syringe retainer 548 caninclude a body 552 and a pair of elastically flexible legs 556 thatextend from the body along the second direction X₂. The elasticallyflexible legs 556 are spaced from each other along a direction that isperpendicular to the second direction X₂ so as to define a gap 560between the elastically flexible legs 556. Each elastically flexible leg556 includes a tab 564 that extends toward the other leg 556 such thatwhen the syringe 324 is moved through the gap 560 along the seconddirection and toward a seated position, the elastically flexible legs556 move away from each other, and when the syringe 324 is in the seatedposition, the elastically flexible legs 556 move back toward each otherso that the tabs 564 engage the bottom shoulder 540 of the syringe 324.Once the syringe retainer and retainer combination are inserted into thelower housing 304, the flexible legs 556 are held in place and can nolonger flex outward thus supporting the syringe 324. In the illustratedembodiment the tabs 564 are disposed at the distal ends of the legs 556.It should be appreciated, however, that the tabs 564 can be disposedanywhere along the legs 556 as desired.

With continued reference to FIG. 27A, the retainer 548 further includesan aperture 572 that extends through the body 552 and into the gap 560and at least one grip 576 that is carried by the body 552 within theaperture 572. The at least one grip 576 is configured to abut thesyringe 324 so as to prevent the syringe 324 from moving through the gap560 along the first direction X₁ after the syringe 324 is in the seatedposition. The grips 576 can be elastomeric portions, ribs, or any otherstructure capable of preventing the syringe 324 from backing out of thegap.

As shown in FIGS. 27A and 22C, the retainer 548 further includes atleast one locking tab 580, such as a pair of locking tabs 580, thatextend outward from the body 552 away from the central axis A. Thelocking tabs 580 are configured to abut the lower housing 304 to therebylock the syringe retainer 548 within the lower housing 304. The lockingtabs 580 can be flexible such that as the retainer 548 is seated in thelower housing 304, the locking tabs 580 flex toward the central axis Aand subsequently move back to their original position when the retainer548 is fully seated within the lower housing 304 such that the lockingtabs 580 engage respective portions of the lower housing 304 to therebylock the retainer 548 and syringe 324 within the lower housing 304. Itshould be appreciated, however, that the retainer 548 can have otherconfigurations as desired. For example, the locking tabs 580 couldextend from the legs 556 as desired.

Now in reference to FIGS. 23, 22C-22E, and 28, the needle guard 316 ismovable relative to the lower housing 304 along the first direction X₁from the first position to the second position when the needle guard 316is pressed against a skin surface, and subsequently movable along thesecond direction X₂ from the second position to a final position whenthe device 300 is removed from the skin surface. As shown in FIG. 28,the needle guard 316 includes a housing 600 and a pair of extensions 604that extend from the housing 600 along the first direction X₁. Thehousing 600 houses the needle 332 when the needle guard 316 is in thefirst position and final positions. As the needle guard 316 moves to thesecond position, the needle 332 protrudes from the housing 600 and isinserted into the tissue.

As shown in FIGS. 23 and 28, the extensions 604 oppose each other andare each configured to move within a respective second channel 506b ofthe lower housing 304 such that the extensions 604 are each disposedbetween the lower housing body 494 and a respective guide 376 of theupper housing 308. As shown in FIG. 28, each extension 604 defines astop 612 that is configured to contact or otherwise abut a respectivehousing latch 510, such as the protrusion 514 of the housing latch 510,when the needle guard 316 is in the first position so as to maintain thehousing latches 510 in interference with the upper housing 308. When theneedle guard 316 moves toward the second position, the stops 612 moveout of contact with the housing latches 510. The housing latches 510 canthen move out of interference with the upper housing 308 so that theupper housing 308 is capable of moving toward the dispensed position.Therefore, the upper housing 308 can be maintained in the pre-useposition until the needle guard 36 has been moved to the secondposition.

With continued reference to FIG. 28, the needle guard 316 furtherdefines an opening 616 in each extension 604 and a needle guard latch620 that extends up from the extension 604 and into the opening 616.Each needle guard latch 620 is resiliently flexible and defines a groove624 at its proximal end and a hinge 628 at its distal end. The needleguard latches 620 are configured to flex about their hinges 628 as theneedle guard 316 moves from the second position to the final positionand when the upper housing 308 is in the dispensed position. As shown inFIG. 28, each needle guard latch 620 defines a sidewall 632 that extendsfrom the hinge 628 to the groove 624. At least a portion of eachsidewall 632 that is proximate to the groove 624 is angled relative tothe first or second directions. The protrusions 514 of the housinglatches 510 can ride along the angled sidewall portions 632 as the upperhousing 308 is moved toward the dispensed position so as to cause theneedle guard latches 620 to flex and when the needle guard 316 movesfrom the second position to the final position. When the device 300 isthen removed from the tissue and the needle guard 316 moves to the finalposition the needle guard latches 620 will flex back toward theiroriginal positions such that the grooves 624 receive the protrusions 514of the housing latches 510 to thereby lock the needle guard 316 in thefinal position.

As shown in FIGS. 29A-29F, the housing latches 510 can be configured toboth selectively maintain the upper housing 308 in the pre-use positionand later maintain the needle guard 316 in the final position. As shownin FIG. 29A, when the upper housing 308 is in the pre-use position andthe needle guard 316 is in the first position, the protrusions 514 ofthe housing latches 510 abut respective abutment surfaces 398 of theguides 376 of the upper housing 308 so as to prevent the upper housing308 from moving toward the dispensed position. As shown in FIG. 29A, thestops 612 of the needle guard 316 abut the protrusions 514 and maintainthe protrusions 514 interference with the abutment surfaces 398. Asshown in FIG. 29B, when the needle guard 316 is moved to the secondposition, the stops 612 are moved away from the protrusions 514 suchthat the housing latches 510 are capable of moving out of interferencewith the abutment surfaces 398 of the upper housing 308 and the upperhousing 308 is capable of moving toward the dispensed position. As shownin FIGS. 29C and 29D, as the upper housing 308 moves toward thedispensed position, the protrusions 514 move into and along the channels400 of the guides 376. As shown in FIG. 29D, the protrusions 514 ridealong the angled sidewall portions 632 and cause the needle guardlatches 620 to flex so that the protrusions 514 can continue theirtravel along the channels 400. As shown in FIGS. 29E and 29F, as theneedle guard 316 moves from the second position toward the finalposition the protrusions 514 ride along the sidewalls 632 until theneedle guard latches 620 flex back toward their original positions andthe grooves 624 receive the protrusions 514 to thereby lock the needleguard 316 in the final position. In this way, the housing latches 510can be configured to both maintain the upper housing 308 in the pre-useposition and lock the needle guard 316 in the final position.

In operation and in reference to FIGS. 30A-30F, the delivery device 300can be configured to deliver a medication. Prior to use, the upperhousing 308 can be locked in the pre-use position by the housing latches510, and the cap 320 can be coupled to the lower housing 304 so as toshield the needle guard 316 and the needle 332. When the device 300 isready to be used, the cap 320 can be removed from the lower housing 304such that the cap 320 removes the needle shield 338 from the needle 332as shown in FIG. 30B.

As shown in FIG. 30C, the device 300 can be positioned against a skinsurface and a manual force can be applied to the upper housing 308 alongan insertion direction (e.g. the second direction) such that as theneedle guard 316 is pressed against the skin surface, the needle guard316 moves to the second position and the needle 332 is inserted into thetissue. As the needle guard 316 moves to the second position the stops612 move out of engagement with the housing latches 510 so that theupper housing 308 is no longer locked in the pre-use position. As shownin FIGS. 30D and 30E, the upper housing 308 can then be moved along thesecond direction and over the middle housing 312. When the upper housing308 reaches the dispensed position substantially all of the middlehousing 312 is covered by the upper housing 308 and the plunger can bevisible within the windows 336 thereby providing visual evidence thatall of the medication has been delivered to the tissue.

Further, when the upper housing 308 reaches the dispensed position, thelocking latches 390 of the upper housing 308 engage the latch members530 of the lower housing 304 to thereby lock the upper housing 308 inthe dispensed position so as to prevent re-use of the delivery device300. As the locking latches 390 snap over the latch members 530, anaudible click is produced that signifies to the user that the upperhousing 308 has reached the dispensed position and is locked in thedispensed position. The upper housing 308 can be permanently locked inthe dispensed position such that the device 300 is not reusable. Itshould be appreciated, however, that the upper housing 308 can betemporarily locked such that the device 300 can be sterilized andreused.

As shown in FIG. 30F, when the device 300 is removed from the skinsurface along a direction opposite the insertion direction the needleguard 316 moves along the second direction to the final position. Whenin the final position, the housing latches 510 interfere with the needleguard latches 620 to thereby lock the needle guard 316 in the finalposition. In this way, the needle guard 316 can be permanently locked inthe final position so that the device 30 is not reusable. It should beappreciated, however, that the needle guard 316 can be temporarilylocked such that the device 300 can be sterilized and reused.

As shown in FIGS. 30B and 30F, the needle guard 316 can be configured tomove a first distance d₁ along the first direction from the firstposition to the second position and a second distance d₂ along thesecond direction from the second position to the final position. Thesecond distance d₂ can be greater than the first distance d₁ to therebysignify to the user that the needle guard 316 is in fact in the finalposition and locked. The needle guard 316, and in particular the housing600 of the needle guard 316 can include a visual indication 640, such asa color band, at a proximal end of the housing 600 that is only visiblewhen the needle guard 316 is in the final position. It should beappreciated, however, that the needle guard 316 can move any distancefrom the first position to the second position and any distance from thesecond position to the final position.

While the foregoing description and drawings represent the preferredembodiment of the present invention, it will be understood that variousadditions, modifications, combinations and/or substitutions may be madetherein without departing from the spirit and scope of the invention asdefined in the accompanying claims. In particular, it will be clear tothose skilled in the art that the invention may be embodied in otherspecific forms, structures, arrangements, proportions, and with otherelements, materials, and components, without departing from the spiritor essential characteristics thereof. One skilled in the art willappreciate that the invention may be used with many modifications ofstructure, arrangement, proportions, materials, and components, whichare particularly adapted to specific environments and operativerequirements without departing from the principles of the invention. Inaddition, features described herein may be used singularly or incombination with other features. For example, features described inconnection with one component may be used and/or interchanged withfeatures described in another component. The presently disclosedembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims, and not limited to the foregoing description.

It will be appreciated by those skilled in the art that variousmodifications and alterations of the invention can be made withoutdeparting from the broad scope of the appended claims. Some of thesehave been discussed above and others will be apparent to those skilledin the art. This includes a multiple-dose design in which one or both ofthe upper and middle housings rise to a partial height and deliver apartial syringe when depressed by the user.

What is claimed:
 1. A method of injecting a medication from a medicationdelivery device of the type including an upper housing, a lower housing,a syringe supported by the lower housing and having a needle, and aneedle guard supported by the lower housing, the method comprising thesteps of: placing the medication delivery device against a skin surfaceso as to cause the needle guard to abut the skin surface, wherein theupper housing is releasably locked with respect to movement toward theneedle by a housing latch that interferes with the upper housing;applying a force against the upper housing along an insertion direction,thereby causing the skin surface to force the needle guard to retractrelative to the lower housing and thereby expose the needle so as toinsert the needle into the skin surface; during the applying step,causing the housing latch to move out of interference with the upperhousing; continuing to apply the force against the upper housing alongthe insertion direction, thereby causing the upper housing to movetoward the needle, thereby driving a medication contained within thesyringe out the needle; moving the medication delivery device away fromthe skin surface along a direction opposite the insertion direction soas to remove the needle from the skin surface and cause the needle guardto advance relative to the needle to a final position whereby the needleguard substantially encapsulates the needle; and locking the needleguard in the final position with the housing latch.
 2. The method ofclaim 1, wherein the continuing step further comprising the step ofdriving a plunger rod into the syringe so as to drive the medication outthe needle.
 3. The method of claim 1, after the continuing step, furthercomprising the step of preventing the upper housing from retracting awayfrom the needle.
 4. The method of claim 1, wherein the medicationdelivery device further includes a middle housing coupled between theupper housing and the lower housing, wherein the continuing stepcomprises the step of progressively covering a body of the middlehousing with the upper housing to thereby provide a visual indicationthat the medication is being delivered.
 5. The method of claim 4,wherein the continuing step comprises the step of causing a frictionmember of the upper housing to rub against a friction member of themiddle housing as the upper housing progressively covers the body tothereby create a friction force between the upper housing and the middlehousing.